Many people set alarms to be awoken from their sleep, such as on a nightly basis before going to bed. Some use a repeated scheduled alarm to be sounded at a specified time every day or every weekday. Individuals may set their device alarms according to appointment times or a work start time, for example, without any regard to the amount of sleep that is recommended or needed for healthy recovery. In many cases, an individual is awoken from their sleep without having achieved the optimal amount of sleep recommended for healthy well-being. In some instances, setting an alarm based on a predefined schedule may cause people to sleep longer than what is needed or recommended, thus wasting valuable time that could be spent on other tasks, or detrimentally impacting their ability to sleep in the near future. However, it may be difficult for humans in modern life to define or measure how much one should sleep to fully recover.